This research project is aimed at the examination of morphological alterations in experimentally produced epilepsy in animals to get insight into some of the alterations and causes for epilepsy in man. By studying these changes in experimental animal models, it is proposed that a structural basis for seizures may be obtained. The animal model of alumina cream has been used thus far because the chronic recurrent seizures are more like epilepsy in man, both clinically and electrically, than are other experimental animal preparations. The alumina epileptic focus has been studied histologically. In order to better define interactions between cells and the brain, tracer experiments with horseradish peroxidase have been performed in normal animals. By building on this base, the present proposal is to: 1) by radioautographic experiments trace the course of alumina in brain to its site of action; 2) study the action of alumina applied to different sites in order to determine which cells are primarily affected; 3) compare the structural changes in experimental animals to excised epileptic foci in man; 4) examine the effects on the intercellular environment and the relationship between cells by use of tracers (horseradish peroxidase) produced by seizures and associated cortical manipulatable events; 5) study the sub-microscopic structure of neuron and astrocytic surface membranes by freeze-etching techniques in normal and epileptic foci.